Improvement in platform-scales



A. B. DAVIS. PLATFORM SCALE.

No. 33,2917. `Patented Sept. 17, 1861.

THE Nonms PETERS ca., wAsHlNcmN, P. c.

eration.

UNITED STATES PATENT OFFICE.

IMPROVEMENT 1N PLATFORM-SCALES.

Specification forming pari of Letters Patent No. 33,297, dated September l'T, iSti.

'['0 ill wit-0m 'may concern: Beit known that I, AUGUSTUS ll. DAVIS, of Philadelphia, State of Pennsylvania, haveinvented a new and useful Improvement in Platformgeales; and I do hereby declare the following to be afull, clear, and exact descriptio'n of the same, reference being had to t-he accompanying drawings, and to the letters. of reference marked thereon.

My invention relates to an improvement in that class of platform-scales which is usedfor weighing loads of hay, coal, and other heavy objects; and my improvement consists in a peculiar arrangement of levers, described hereinafter,wherebyr a platform of extended length may be substituted for a shorter platform after a simple adjustment of the said levers and their appurtenances,and without resorting to a general dismemberment and reconstruction of the scale, which under the above circumstances wouldbe demanded by a platform-scale of the ordinary construction.

In order to enable others skilled in the art to make and use my invention, I will now proceed to describe its construction and op# On reference Ato the accompanying drawings, which form a part of this specification,

Figure l is an end view of a platform-scale with my improvements; Fig. 2, a plan view with part of the platform removed, and Fig. 3 a side view.

Similar letters refer to similar parts throughout the several views.

A represents -the foundation of the scale, and to this foundation are secured the two beams B and B', which serve' as guides for the two transverse beams C and C", and which are also secured to the foundation. Near one end of the beam (l issecured a chair E, and near the opposite end of the beam a similar chair E the beam ,C at the opposite end of the foundation being furnished with similar chairs. Each chair has a projection a, carrying a elevis b, the clevis of the chairE carrying the lever F and that of the chair E carrying the lever G. Theselevers E and G are connected together by the clevis d, and the latter lever is connected to the short 4arm of the lever II by a clevis e, the fulcrum of the latter lever being in the clevis f, which is secured to an eyebolt h, so connected to the beam C as to readily turn therein.

secured to a beam N, resting on and guidedV by the beams P P of the foundation A. The graduated scale-beams .I and K are in the present instance constructed and arranged in the manner described in my patent of February 2G, 1861. As they form no part of my present improvement, however, and as any of the usual scale-beams maybe used in place of those shown, an explanation of them will he unnecessary.

The platform consists of two longitudinal beams Q'and Q', connected together by the boards R, the beam Q resting on the knifeedges y on the short arms of the two levers F F and the beam Q on similar knife-edges o'n the shortarms of the levers G G, so that any depression of the platform caused by a weight on the same will communicate a movement` through the medium. of the four levers F F and G G, and the two diagonal levers II Il to the scale-beams K and J, by-means of which the weight -of the object on the platform may be ascertained.

An ordinary platformscale is so constructed an d its levers are so arranged that should an extension of the platform be required to re ceivo objects of a length for which the original machine was not designed it becomes necessary either to make anew machine or, what is a most expensive and tedious operation, to entirely dismember and reconstruct the old one. This is not the case with a machine constructed on the plan above described, for, after withdrawing the necessary bolts or other fastenings which secure the beams C and C to the foundation A, these beams, with their chairs E and 'l' and their levers F and G, can be moved from or toward each other, always however, retaining their position at right augles to the platform. An alteration in the posit-ion of the beams C C will of course de 2 ease? mand an alteration in the angular position of the levers II. Forinstance,in Fig. 2 the beams C and C', withtheir levers, are shown as having been adjusted from a position in which a short platform was required to one which requires a longer platform, the dotted lines x showingthe position occupied by the levers F and G, and the dotted lines 1j the position of the lever Il prior to the extension of the platform. Orradjustingr the beams and levers for the reception of an extended'platform the levers F and G and lever I-I will occupy the positions shown in plain lines, the angle of the lever II bein g changed, and this change involvingthenecessityof a change in the position of the frame which carries the graduated scalebeams J and K, the base Not this frame haviupT been moved nearer to the edge of the platform from the position shown by dotted to that illustrated by plain lines, Fig. 2. It will now be'seen without further description that when an extended platform is required Vfora scale constructed as described above,

all that is necessary is to remove the fastenings which securer the beams (ly an C and those which secure the base T of the frame Which carries the graduated levers, then to move the beams apart from each other and to adjust the base N to the position demanded by the change in the position ofthe levers H H, after which the parts may be again se cured and the extended platform 'deposited in its place. As the eyebolts h to which the levers H are con ne'cted can turn freely, the said levers Willadjust themselves to any angle required. It will be understood that the under side of the beams Q and' Q are furnished with recessed plates of meta-l forresting on the knife-edges ot' the levers F and G,

agonal levers H II and the adjustable framev which carries the graduated scale beam or beams, the whole being arranged 'substantially as and forthe purpose herein set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

' A. B. DAVIS.

Witnesses;

HENRY HoWsoN, CHARLES E. FOSTER.' 

